Who would have guessed that the deliberately archaic-minded rock of the Decemberists would reach critical mass? It's understandable with an album as relentlessly tuneful as the new Picaresque (Kill Rock Stars), though. 8 p.m. Thurs., Oct. 27–Fri., Oct. 28. $15. Showbox, 1426 First Ave., 206-628-3151, www.showboxonline.com. MICHAELANGELO MATOS